@Rich: From my point of view, you did a really good job! I mean you kept compatibility for old i486 CPU and improved the search comfort, BOTH in GUI and cmd line. Using just awk and shell, the search time (for you) is less than 2 seconds!
The number of extensions (in the future) will NOT dramatically increase (because missing MORE significant number of developers).
My assumptions are that the SIZE of database will NOT increase too much (+20% maxim as GZIP-ed) and the database is LOCATED in RAM memory, plus the UPDATE of the database is not so often performed. So, it seams that by this path you will soon arrive at diminishing return (Pareto principle). All is just an intellectual challenge, which I like.
Even if you can achieve, lets say search in 1/1000 seconds, which is 2,000.00 time faster than 2 seconds, the practical implication could be exploited only in loops or pipes programs, but not in GUI interface.
I wonder what (old?) computer specification you used (CPU, HDD, RAM), if you want to share, for your test.